WASHINGTON (CNN) -- A super PAC backing Wisconsin Gov. Scott Walker said it will spend nearly $7 million on its first major ad buy in Iowa.

The buy, which covers television and radio ads, is expected to be finalized Wednesday. It's part of a push to boost Walker's fortunes in early nominating states before the airwaves grow even more crowded, according to a senior official with the group, called the Unintimidated PAC.

In the coming weeks, the group also plans to spend seven figures on advertising time in New Hampshire, South Carolina and Nevada.

\"Governor Scott Walker is the only candidate who has fought for big, bold reforms to our biggest challenges and actually won those fights,\" said Brad Dayspring, a senior adviser for the super PAC. \"This is the first phase of telling his story -- a conservative governor from a blue state who has challenged the status quo, fought the entrenched special interests, and enacted conservative reforms to reform government from the bottom up -- to voters in early states who are looking for a fighter who does more than make promises.\"

Given the crowded GOP field, a number of campaigns are making early ad buys before the market grows saturated and ad rates increase. The pro-Walker group expects its ads to begin airing in Iowa in early September and to run through early February.

Walker's advisers acknowledge Iowa is a must-win for the candidate, but the planned television buys in the first four states indicate his allies are working to ensure he can appeal to a broad set of voters beyond the Hawkeye State. That strategy could offer Walker more options to map a path to victory, but it also comes with a hefty price tag.

Walker's allies raised $20 million for the super PAC in the second quarter of 2015. However, half of that money came from just two sources, which could pose a challenge over the long haul if Walker is unable to expand his fundraising base.

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